Photonic activation of reactants for sub-micron feature formation using depleted beams

ABSTRACT

A fine feature formation method and apparatus provide photon induced deposition, etch and thermal or photon based treatment in an area of less than the diameter or cross section of a STED depleted laser beam. At least two STED depleted beams are directed to a reaction location on a substrate where a beam overlap region having an area smaller than the excitation portion of the beams is formed. A reactant or reactants introduced to the reaction region is excited by the combined energy of the excitation portions of the two beams, but not excited outside of the overlap region of the two excitation portions of the beams. A reactant is caused to occur only in the overlap region. The overlap region may be less that 20 nm wide, and less than 1 nm in width, to enable the formation of substrate features, or the change in the substrate, in a small area.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of U.S. Provisional Patent ApplicationSer. No. 61/863,740, filed Aug. 8, 2013, and of U.S. Provisional PatentApplication Ser. No. 61/884,744, filed Sep. 30, 2013, each of which isincorporated herein by reference.

FIELD

The present disclosure relates to the forming of sub-micron sizedmaterial features, for example sub-micron sized trenches or lines,submicron sized pillars or apertures, and the like, wherein thesubmicron sized features are directly formed in situ with a depositionmaterial, or are formed in-situ in a previously formed thin film,without the need for traditional photolithographic processing wherein aphotoresist is exposed and developed, and the resulting pattern istransferred into an underlying material layer. In particular, an energybeam is provided which has sufficient energy to activate an etch or adeposition reactant(s) in a nanometer dimensioned region, and depositionor etching reactant(s) which are introduced into the nanometerdimensioned region are activated to from a deposition material or anetchant species in the region. The beam may be rastered across aworkpiece, such as by moving the workpiece with respect to the beam, toeffectuate the writing of a line or the etching of a trench, and as aresult deposited and etched features of a nanometer sized dimension maybe formed.

BACKGROUND

The relentless pursuit of smaller and smaller features in integratedcircuits is approaching the limits of traditional photolithographictechniques. In these techniques, a photoresist is coated on a substrate,and a mask pattern is projected by electromagnetic radiation passingthrough the mask and onto the resist causing the resist to becomeexposed in a pattern corresponding to the features of the mask. Theresist is then “developed” and rinsed in a solvent to remove a portionthereof and leave the photoresist, having the resulting projected maskpattern, on the surface of the substrate or on a film layer, such as ahard mask layer, located on the substrate. The material underlying thephotoresist is etched, typically in anisotropic plasma based underlyingfilm selective etching chemistry, to transfer the photoresist patterninto the underlying layer. Thereafter, the photoresist is removed byashing or other removal techniques, and the substrate is wet cleaned toprepare it for the next process. However, feature sizes have shrunkbelow that which can be imaged (resolved) using these traditionallithographic techniques, and to extend the use of traditionallithographic techniques to form these features, subtractive techniques,such as double and triple patterning, have been employed. In theseprocesses, to achieve the smaller feature sizes on the order of 40 orfewer nanometers, the hardmask may be patterned and used to etch anunderlying patterning layer, and the hardmask removed and replaced withan additional hardmask, and the process of coating with resist, exposingthrough a mask, etching the hardmask, and then etching the patterninglayer may repeated one or more times, to pattern the patterning layerbefore patterning the ultimate material layer in which the sub-40 nmfeatures are formed. Nonetheless, despite these advances, currentlithographic techniques will be insufficient to meet the reduceddimensions called for in future semiconductor technologies.

Modern photolithography depends upon the concept of a sacrificial“photo” exposed resist, wherein areas of the resist that are exposed tolight behave differently than those which do not. Because thesetechniques rely on electromagnetic radiation, diffraction limits thesmallest feature size that can be imaged or resolved. Additionally, evenif the feature size may be imaged, the energy entering the photoresistmay also be scattered therein, leading to irregular exposure of theresist across the depth of the resist. As a result, the feature sizewhich is exposed will actually be larger than the smallest resolvableimage, and, it will have non-uniform sidewalls or other irregularities.

Currently, high-volume manufacturers are using deep-ultraviolet (DUV)photons, such as photons with a wavelength of 193 nm, to expose aphotoresist material. Manufacturers are also using liquid immersiontechniques and techniques such as the aforedescribed multiplepatterning, to create patterned features on substrates of a small size.

Recently, laser beam lithography has again been investigated as amechanism to expose very small features in photoresist and thereby breakthrough the resolution limitations of traditional mask basedphotolithographic techniques by creating small cross section, high powerlaser beams. Fischer and Wegoner, in Laser and Photonics Reviews, 7, No.1, 22-44 (2013) discuss an idea of using a stimulated emission depleted(STED) beam to expose the resist three dimensionally, i.e., in acolumnar fashion, and thus direct laser write a feature through the fulldepth of the resist. In order to reduce the effective cross section ofthe resist which is exposed to sufficient energy to be polymerizedthereby, two laser beams, a “normal” beam and a depletion beam, are usedto form a STED beam. The excitation beam excites the polymer in thephotoresist to cause it to polymerize, and the depletion beam reducesthe energy in the photoresist before the photoresist polymerizes, thuskeeping the photoresist from polymerizing where the depletion beam andthe excitation beam energies overlap. Improved resolution occurs wherethe spatial maximum of the excitation profile of the normal beamcorresponds with the local zero of the depletion profile of thedepletion beams, i.e., the depletion beam is configured to spatiallysurround the excitation beam, and cull, from the resulting exposedregions of the photoresist, the polymerizing effect of the skirt regionof the Gaussian beam. As a result, the portion of the excitation beam inwhich the polymerizing reaction is not cancelled by the depletion beamhas a very sharp, nearly rectangular energy profile across its widthrapidly reducing at the edges of the profile to an energy level belowthe polymerization energy of the resist, such that a sharply definedhigher energy region is formed in the beam as opposed to traditional,Gaussian profile, beams. However, even using this direct laser beamexposure system, repeatable and sharply defined features smaller than 20to 30 nm are difficult to achieve, in part because of the limit in thesize of the sharply defined region of the beam, and in part because ofinherent migration of polymerization in the photoresist being exposedfrom the location where the beam enters the photoresist into adjacentlocations.

SUMMARY

In the embodiments herein, two different photon sources, such as lasers,soft x-rays, and the like, wherein each may have similar or differentphotonic energy levels, are directed to, but only partially overlap, afeature location on a substrate to be processed. The extent to which thebeams overlap defines the size of the feature location at which photonsof the two different beams are received on the substrate.Simultaneously, a precursor material is presented at the featurelocation, such that the photons of both beams may be absorbed by themolecules or atoms of the precursor, thereby increasing the reactivityof the precursor(s) and causing a reaction to occur only in the limitedarea of overlap of the two beams. Adjacent to the overlap region of thetwo beams, the energy of a single beam is insufficient to initiate theactivation of the precursor.

In one aspect, to enable a more precise definition of an area where theoverlapping beam energy is sufficient to cause a reaction to occur, twolaser beams, at least one of which is formed by an excitation beam and adepletion beam, are directed to a reaction location on a surface suchthat the centers of the beams are offset at the reaction location, butthe profile of the beams overlap, such that in the desired area in whichthe beams overlap, a region is formed where the photon energy of the twobeams is sufficient to cause the reactants to have the desired reaction,but in the areas immediately surrounding the reaction location, thecombined photon energies of the two beams are insufficient to cause thereactants to react, and thus a localized reaction zone may be formed.Where both beams are laser beams having an excitation source and adepletion source, a beam diameter of each beam over which the ultimatelycombined energy of the two beams is sufficient to cause reaction of thereactants may be well below 100 nm, as low as on the order of 20 nm. Asa result, where the beams have a circular cross section, a bi-convexovoid pattern having a width on the order of less than 20 nm,specifically of a single digit to tenth of a nanometer size, may bereliably formed to control the size of the reaction space in which anadditive or subtractive reactive process may occur.

In one aspect, the precursor is a precursor(s) which, with theintroduction of sufficient energy, will react to form a material usefulin the production of film layers on the substrate, or for the reductionof such film layers through a reaction which removes the film layermaterial, i.e., etching. However, outside of the region of overlap ofthe two beams, photons in the high energy central region of only onebeam are received by the precursor, and thus sufficient energy is notintroduced to cause the reaction to occur.

As an example, the activation of silane, trichlorosilane, tri-silane,etc., is known to react to deposit silicon. However, the two gasesrequire an introduction of energy, provided for example by lamps orplasma, to drive the reaction to occur. In these systems, the reactionoccurs wherever the lamp or plasma energy is sufficient to drive thereaction to occur, which occurs over a large area of a substrate, oftenthe entire surface thereof. By using overlapping beams having twodifferent photon energies, as described herein, only where the beamsoverlap will sufficient energy be present for the reaction occur, andthus silicon will be deposited only in the overlap region.

In a further embodiment, the two different lasers are configured as STEDlasers, such that the region in the perimeter of the beam profile isenergy depleted, further reducing the diameter of the beam above adesired threshold photon energy, whereby the size of the overlap of thetwo beams, in an energy range where two photon based reactions canoccur, is even further reduced.

DETAILED DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentinvention can be understood in detail, a more particular description ofthe invention, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

FIGS. 1A and 1B show features of an electromagnetic beam, and FIG. 1Cshows the result of overlapping two of the beams of FIGS. 1A and 1B.

FIGS. 2A and 2B are representative drawings of a depletion beam usefulfor combining with the beam of FIGS. 1A and 1B.

FIGS. 3A and 3B graphically show the effect of combining the beam ofFIGS. 1A and 1B with the depletion beam of FIGS. 2A and 2B.

FIGS. 4A and 4B show the overlap of two of the beams of FIGS. 3A and 3B.

FIG. 5 shows a configuration of a beam combiner for combining a beams ofFIGS. 1A and 1B with a depletion beam of FIGS. 2A and 2B.

FIG. 6 is schematic representation of a chamber useful for photonicdeposition using partially overlapped depleted beams in conjunction witha deposition precursor(s).

FIG. 7 demonstrates the effect of sequential photonic deposition inadjacent areas of a substrate.

FIG. 8 demonstrates the use of sequential photonic deposition to form aline on a substrate.

FIG. 9 is a schematic representation of a chamber useful for photonicdeposition or etching using partially overlapped depleted beams inconjunction with a deposition or an etch precursor(s).

FIG. 10 is a representative view of two overlapping parallel depletedbeams.

FIG. 11 is a schematic view of a partially etched feature in a filmlayer using the overlapping beams of FIG. 10 in conjunction with anetching precursor.

FIG. 12 is a schematic view of two partially etched features in a filmlayer using the overlapping beams of FIG. 10 in conjunction with anetching precursor.

FIG. 13 is a schematic view of a fully etched and a partially etchedfeature in a film layer using the overlapping beams of FIG. 10 inconjunction with an etching precursor.

FIG. 14 is a schematic representation of the geometric limitationsimposed on etching and deposition processes where the two depleted beamsconverge at the substrate.

FIGS. 15A to 15D are schematic representations of various apparatus forconcurrently providing a plurality of overlapping beamlets to asubstrate.

FIG. 15E is a schematic representation of a substrate undergoingprocessing using one of the apparatus of FIGS. 15A-D.

FIG. 16 is a partial frontal view of a micro-mirror array useful forcontrolling the direction of a beamlet to a position on, or off of, asubstrate or an overlap location on a substrate.

FIG. 17 is an enlarged partial sectional view of the micromirror arrayof FIGS. 15A to 16.

FIGS. 18A to 18F demonstrate the results of one method of writingmultiple features of different dimensions on a substrate.

FIG. 19 is a schematic representation of a beam splitting andcontrolling apparatus for simultaneously providing a plurality ofparallelly disposed and overlapping beamlets to a substrate.

FIG. 20 is a schematic representation of a photonic treatment system fora workpiece employing a sheet beam source.

FIG. 21 is an enlarged view of a micromirror array of the photonictreatment system of FIG. 20.

FIG. 22 is a sectional view of the micromirror array of FIG. 21.

FIG. 23 is a plan view of a workpiece in a chamber undergoing photonictreatment.

FIG. 24 is a plan view of the wafer and chamber of FIG. 23, wherein theworkpiece is undergoing further photonic treatment.

FIG. 25 is an electron energy diagram of a precursor.

DESCRIPTION OF THE EMBODIMENTS

Described herein are several configurations of a photon deposition oretch system, whereby a combination of photons supplied by two or morebeams having different wavelengths are received in a small target areain the presence of a reactant, wherein neither photon energy issufficient to cause a desired reaction to occur, but the temporal andphysical presence of the two photons or groups of photons, together withthe reactants, causes a desired reaction to occur.

Referring first to FIGS. 1A to 1C, a standard beam profile 10 of a laserbeam, and the effect of overlapping two such beams, is shown. In theprofile 10 shown in FIGS. 1A and 1B, the beam has a peak energy 12 whichtapers off to either side thereof following a Gaussian profile. The halfwidth full maximum energy level 14 of the beam is the profile shown inFIG. 1A. In FIG. 1C, the effect of combining by overlapping two Gaussianbeams with the same energy profile is shown in dashed line profile.

Now referring to FIGS. 2A and 2B, a depletion beam 20, which is used incombination with the standard beam 10 as the excitation beam 10 to forma STED beam 30 of FIG. 3A, is shown. As shown in FIG. 2A, the depletionbeam 20 is red shifted in comparison to excitation beam 10, and it has adepleted central region 22 with an intensity peak 24 surrounding thedepleted central region 22, i.e., it has a doughnut shaped intensityprofile created by passing the depletion beam through a vertex phasemask. The red shifted beam energy causes a reduction in excitationenergy of previously excited species where the depletion beam 20 and theexcitation beam 10 overlap. When the beams of FIG. 1 and FIG. 2 arecollinearly combined, as is shown in FIG. 3, a depleted excitation beam30, having a substantially smaller high intensity central region 32 thanthe width of the beam of FIG. 1A, and a significant taper in beam energyin the skirt region 34 of the beam immediately adjacent thereto, isformed. Basically, the beam energy profile, across its width, approachesa rectangular shape. Additionally, the greater the power of thedepletion beam 20, the sharper or more rectangular the resultingdepleted excitation beam 30 profile, i.e., where a laser has aresolution of 300 nm without the overlay of the second beam 30, aresolution of 20 nm (i.e., a spot diameter at the focal location) can beachieved by imposing a depletion beam power on the order of 500 Mw/cm².For a 10 to 100 nsec pulse, a depletion beam on the order of 1E7 W/cm²is used.

In operation, the depletion beam 20 peak intensity overlies theperimeter of the excitation beam, and in that region, the red shiftedenergy of the depletion beam de-excites the reactants present in thatregion which were excited by the lower energy in the skirt of theGaussian beam, resulting in a beam having sufficient energy to cause theatoms and molecules of the reactant(s) to remain excited only in thecentral region of the beam within the circumference of the doughnutregion.

Referring now to FIGS. 4A and 4B, the use of two such STED depletedbeams 40, 50 to form an overlap region 60 incorporating a portion of thefirst STED beam 40 and the second STED beam 50 is shown. In FIG. 4B, theeffect of overlapping the depleted beams 40, 50 is shown, and comparedto the overlapping of two Gaussian profile beams as shown in FIG. 1C isclearly contrasted. In particular, the skirt regions are regions wherethe reactants excited by the energy in the skirt region of theexcitation beam are de-excited by the red shifted depletion beam, suchthat the overall energy peak occurs in region 60, and thus there is adistinct region of overlap where the drop off from a high energy tonearly no beam excitation of species is defined. In FIG. 4B, the highenergy excitation capability present in the overlap region 60 is highlydefined (as shown in dotted line profile) compared to the skirt regions68, 70 of the two beams. As shown in FIG. 4A, the beams 40, 50 arefocused on a limited area 62 of a substrate 64 (only partially shown),and each has a beam energy profile of the STED beam 30 of FIG. 3. In theembodiment of FIG. 4A, the depleted skirt region 68 of beam 40, and thedepleted skirt region 70 of beam 50 intersect in area 72 of thesubstrate 64, such that an ovoid overlapping region 60 of thenon-depleted high energy central regions 32 (FIG. 3) of the two beams40, 50 is formed. The beam energy is configured such that, within theovoid overlapping region, a photon from one beam, for example beam 40 isnot sufficient to cause a reactant located immediately over thesubstrate 64 and within the ovoid overlapping region 60 to reach areaction state, such that when the second beam 50 supplies a photonwhich when absorbed by the molecule in the excited state as a result ofinteraction with the first photon, is sufficient to drive a depositionor etch reaction of the reactant. The reactant(s) is selected such thatthe combined energies of the high energy regions 32 of the two beams aresufficient, when spatially and temporally aligned, to cause a desireddeposition or etch reaction to occur, but where the two beams 40, 50overlap but the two high energy regions 32 thereof are not overlapping,for example at location 74 where the high energy region of beam 50overlaps the skirt 86 of beam 40, the combined energies are insufficientto cause the reactants to react deposit or etch a material. Thus,because these two beam (photon) energies are spatially present only inthe ovoid overlapping region 60, the reaction occurs only in the ovoidoverlapping region and thus a very small feature may be deposited oretched.

As is also shown in FIG. 4A, although the full overlap of the fullprofile of the two STED beams 40 and 50 may be significant, the actualoverlap where sufficient energy for reaction will be present is verysmall, as shown by dimension 66. For example, where the beam 50 fullwidth (3 standard deviations) across the edge of the skirt 70 is on theorder of 40 nm, the width 66 of the ovoid region may be on the order ofless than 10 nm, even less than 5 nm. As a result, a very small spotsize may be created where direct photonic writing of a film layer onemolecule thick (resulting from a reaction of a molecule or atom as aresult of receipt of two photons of different energies by the two beams40, 50), or etching by individual etchant reaction molecules in theovoid region, is possible. The thickness of the film deposited, or theetch depth of the underlying film, is a function of the absorptioncross-section of each precursor at the wavelength of the photons, thequantity of photons arriving at the overlap locations over the durationof time that the two beams are on and overlapping, and the availabilityof deposition or etch reactants at the overlap site during that sameperiod. Thus, using an extremely short pulse of a very low concentrationof reactive precursor can result in very thin features on the order ofone atom thick. Longer overlap times and higher precursor concentrationwill yield thicker features. Where the overlapping STED beams are usedto activate the reacting (final) precursor in atomic layer deposition oretch processes, single atom thick features may be created. Hence, thesystem of two depleted beams, for example two STED depleted beams, canbe used to replace traditional photolithographic film forming, maskexposure, develop and strip steps to form features by additive orsubtractive atomic and molecular scale photonic reaction on a singledigit nanometer scale, thereby significantly reducing the number ofsteps, and substrate handling, to form such features.

To ensure temporal overlap of the photons of the first and second beam,both beams 40, 50 may be maintained in a constant on state during aperiod of deposition. Additionally, and more preferably, the first beam20 may be maintained in a constant on state, to continuously excitemolecules and atoms of the reactant(s) to an excited but not yetreactive state within the span of the high energy region 32 thereof, andthe second beam 50 may be pulsed, such that in the ovoid overlappingregion 60 second photons, provided by beam 50, and at the same ordifferent energy than a photon provided by beam 40, are absorbed by thereactant resulting in the deposition or etch reaction within the ovoidregion 60.

Additionally, it is contemplated that both the first and the secondbeams 40, 50 may be pulsed. Because the excited state provided by thefirst beam photons is temporary, the timing of the pulses of the secondbeam 50 compared to the pulses of the first beam 40 will dictate whethera reaction occurs.

Referring now to FIG. 5, an arrangement for the formation of thedepleted beam is shown schematically. In this example, the combining oftwo laser beams, an excitation and a depletion beam, are schematicallydescribed. As shown in FIG. 5, a beam combining chamber is coupled to afirst excitation beam source 102A and a second depletion beam source102B, such that a combined, collinear output of the two beams 238 mayresult. Specifically, chamber 299 includes a first window 202A alignedwith the projection of the beam 224A emanated from excitation source102A, and a second window 202B aligned with the depletion beam 224Bemanating from depletion beam source 102B. In this aspect, beam 224Aenters the chamber through window 202A, and is reflected 90 degrees bymirror 204, then passes through a resolving aperture 205A in resolvingplate 206A where it is again reflected 90 degrees, to a path parallel tothe entry path into the chamber 299, by a half silver mirror(beamsplitter) 209 and coextensive with depletion beam 224.

Depletion beam 224 enters chamber 299 through the second window 202B andthen passes through resolving aperture 205B in resolving plate 206Bbefore passing through half silvered mirror 209 where it becomescoextensive with, and axially aligned with, excitation beam 224A. Thecombined beams 238 then pass through a second half silvered mirror,where a portion 232 of the beam is sent to an energy analyzing stationand the main beam passes a blanking shutter 220 and out through anoutlet window 222 to form beam 50. By actuating the shutter 220, thebeam 50 emanating from chamber 299 may be periodically blanked in thechamber 299, such that the second beam 50 may be only periodicallypositioned to overlap on the target location surface where a reaction isintended to occur.

Referring now to FIG. 6, a schematic of a process chamber for carryingout photon based reactions on a workpiece surface is shown todemonstrate the basic features of the deposition or etching process. Inthis figure, the workpiece is a substrate, such as a semiconductorsubstrate useful for the fabrication of integrated circuit devices.

As shown in FIG. 6, a chamber 300 includes a platform 310 therein ontowhich a substrate 320 may be placed for processing. Additionally, thechamber 300 includes an access port 330, such as a gate or slit valve,by which a substrate 320 may be loaded into, and removed from, thechamber 300, such as by a robot having an end effector which isconfigured to place the substrate 320 onto, and remove the substrate 320from, the platform 310, as is well known in the art of semiconductordevice manufacture. Additionally, in this embodiment, the platform 310is configured to move in the X direction (parallel to the plane of thepage of FIG. 6), the Y direction (into and out of the plane of the pageof FIG. 6), and the Z direction (upwardly and downwardly with respect tothe base 302 of the chamber 200). The platform 310 may also beconfigured to rotate about the center thereof.

The chamber 300 further includes a first chamber window 350, and asecond chamber window 352, which in this embodiment are located on thecover portion 304 of the chamber 300. The windows are configured to beable to seal against the chamber cover portion 304, but are alsotransmissive to light energy provided by the beams 40, 50 previouslydescribed herein with respect to FIG. 4. Furthermore, there are provideda plurality of reactant inlet ports 360, in this case ports 632 and 364,a background gas port 366, and an exhaust port 368.

The beams 40 and 50 are generated by energy sources 340, each of whichmay have a first emitter 342 and a second emitter 344. The first emitter342 may be a source of an excitation beam while the second emitter 344may be a source of a depletion beam. The energy source 340 may includeoptics described elsewhere herein for combining the excitation anddepletion beams to form the STED beams 40 and 50. Each of the energysources 340 may include a firing control module 346 that controlsrelease of energy pulses from the emitters 344 and 342. An electronictiming box 348 may be coupled to each firing control module 346 tosynchronize pulsing or firing of the two STED beams 40 and 50. In thisway, precise control of pulse and duty cycle timing may be exercised toperform the methods described herein.

In this embodiment, beam 40 enters chamber 300 through window 350, andbeam 50 enters chamber 300 through window 352. In this embodiment, thebeams 40, 50 are stationary, i.e., the path of the electromagneticenergy is fixed, such that the beams are configured to intersect, in thefashion of FIG. 4, at reaction region 370. Reaction region 370 has theovoid cross section shown in FIG. 4, and, is fixed three dimensionallyin the x. y and z directions within the chamber 300.

To perform a process to cause a reaction in the chamber in the reactionregion 370, a substrate 320 is loaded onto the platform 310 through thevalve 330, and the valve 330 is closed. The exhausting or pumping of thechamber 300 reduces the chamber pressure to a sub-ambient pressure, forexample, in the millitorr range, and a background gas, such as the inertgas argon, is flowed into the chamber through background gas port 366until a stable pressure is reached based on the incoming flow of argonand the exhaust flow through the exhaust port 368. Once a steadypressure is reached, reaction gas(es) are flowed through the reactiongas ports 362, 364, to provide one or more reactive gases over thesurface of the substrate 320, particularly in the reaction region 370,separately or in a mixture. Alternatively, in some reactions, only onereactant need be supplied through only one of ports 364, 362. The beam40 is supplied to the chamber 300 through the window 350, and the secondbeam 50 is supplied through the window 352 to intersect at reactionregion 370. As a result, the combined photon energy of the beams 40, 50in the ovoid reaction region 370 is sufficient to cause the reactant(s)to react and cause either a localized deposition or etch reaction in theovoid reaction region 370.

To cause the reaction to occur at different locations on the substrate320, the platform 310, on which the substrate 320 is held, may be movedin the x and y direction, thereby moving the relative position of theovoid reaction region 370 on the substrate 320. Additionally, where thebeams intersect at the deposition region as shown in FIG. 6, thesubstrate 320 may also be moved in the z direction to ensure that thesize of the ovoid overlap region 370 does not change as material isdeposited in the region and the distance from the top of the depositedmaterial to the beam sources is reduced.

Referring to FIG. 7, there is shown the photonic writing of a line onthe order of 5 to 10 microns in width W across the surface of asubstrate 320 using the chamber 300 of FIG. 6. As is shown in FIG. 7, afirst ovoid region 400 is formed on the substrate and a depositionreactant, for example silane, is provided through one of the reactiongas ports 362, 364 of FIG. 6, and it forms a thin silicon layerapproximately one or more atoms thick across the span of the ovoidregion to form a first ovoid deposition region 402. The substrate isthen incrementally moved less than half the long dimension D of theovoid, and the deposition process is repeated to form a second ovoidregion 406, leaving a first region 402 of the first ovoid region with adeposited Si layer approximately one or more atoms thick and a secondportion 404 of the first ovoid region 400 having a thickness ofapproximately twice the thickness of the first deposition formed wherefirst and second ovoid regions 400, 406, overlap. The substrate 310 isagain moved the same distance in the same direction, and a third ovoidregion 410 is formed, partially overlapping the first and the secondovoid regions 402, 406, providing a three times thickness layer in aportion of the first ovoid region 402, and a two times thickness layerin a portion of the second ovoid region 406. By repeatedly moving thesubstrate in this manner, a line 420 may be directly photonicallydeposited on the substrate 320, having a thickness on the order of threeor more atomic layers of Si. To increase the thickness of the line 420,the platform 310 on which the substrate 320 is held may be lowered, onthe order of the thickness of the line 420, and the photonic depositionprocess is repeated over the length of the line 420 one or more times,or the duration of the beam overlap period is increased. As a result, aline 420 having the width of the ovoid reaction region 370 may be formedon the surface of the substrate to a desired thickness.

Referring to FIG. 8, the resulting line is shown. As can be seen in FIG.8, the line sidewall includes a number of “scallops” or arced regions,extending or bulging the line outwardly in a direction perpendicular toits length. The relative size of these scallops in comparison to thewidth of the line, and the depth of the line, is adjustable by adjustingthe overlap of each ovoid region formed during deposition of the line.For example, if the second ovoid region 406 of FIG. 7 is formed bymoving the center of the ovoid by ⅕ the long dimension D of the ovoid,then ten scallops will result per ovoid region length, along the lengthof the line. If the second ovoid region is formed such that its centeroverlaps the end of the first ovoid region 402, and the number ofscallops in the line per length D of the ovoid region is two. Likewise,in the later scenario, the depth of the line, except at the beginningand end (first and last ovoid, will be two or more deposition layersthick, whereas in the first scenario, it will be ten or more depositionlayers thick, where each layer may be as thin as one atom. Thus, to forma smoother sidewall, using the ovoid projection for reaction, the lengthadjustment of the ovoid must be smaller, and the resulting line will bethicker, but the writing time will be longer. However, as the likelydesired thickness of the line may be significantly thicker than ten ormore atoms thick, the overall throughput where multiple lines need beoverwritten will not suffer.

Additionally, as will be described further herein, during the writing ofthe line 420, only one, or both of the beams 40, 50 may be pulsed, i.e.,intermittently directed to the writing area of the line. For example,one beam 40 may remain on, and move along the substrate in the path ofthe line 420, and the second beam 50 may be intermittently provided, atthe time when the first beam 40 has reached the proper overlap positionwith a previously deposited ovoid region. The beam 50 may be pulsed byblanking the beam 50 off of the line 420 being written to another areaof the substrate which is not occupied by another beam, or completelyoff of the wafer, and even by a shutter at the beam source.Alternatively, both beams may be pulsed, such that as the support 310moves the substrate 310 laterally or in the z direction, the beams 40,50 are both “off” until the next writing position for deposition of anovoid region is attained, and they are then pulsed at the writinglocation. Again, off includes blanking the beams to non-overlappinglocations on the substrate, within the chamber, or with a shutter at thebeam source.

Referring now to FIGS. 9 and 10, there is shown an additionalembodiment, where the apparatus of FIG. 8 is modified for etching, or“photonic” removal processes. In this embodiment, the two beams 40, 50are overlapped, such that the centerlines of the two beams are paralleland offset from one another, such that an overlap region 1000 (FIG. 10)is formed which extends collinearly of both beams 40, 50 in the overlapregion thereof, to form the ovoid overlap region of the two beams 40, 50shown in FIG. 4. In contrast to the embodiment of FIG. 6, in thisembodiment, the overlap region extends the height of the chamber, andthus the reaction of the etchant reactants will occur along the lengthof the overlap region.

Referring now to FIGS. 11 to 13, the effect of an etching reaction usingthe overlapped beams 40, 50 is shown. In this case, beam 40 extends overthe substrate by width 40 a, and beam 50 extends over the substrate bywidth 50 a, with an overlap region 52 extending as an ovoid column fromthe substrate 310 and having the cross-section shown in FIG. 4. As shownin FIG. 11, a partial view of substrate 320 includes a silicon oxidelayer 322 formed thereon, through which a feature 324 (FIG. 13) isdesired to be formed. The feature 324 to be etched has a width 326 onthe order of less than 20 nm wide, for example 5 nm wide. To etch thisfeature, the chamber 300 of FIG. 9 is pumped down to the millitorr rangeby exhaust 368, and argon or another inert background gas is introducedthrough gas port 366, until a stable pressure is reached. Then anetchant selective to silicon oxide is introduced through port 362, suchthat the gaseous reactant overlies the substrate 320. Then beams 40 and50 are activated, to etch the layer 322.

After a first etch step, the silicon oxide layer 322 has a small recess328 formed therein, which extends to a depth equal to the quantity ofSiO₂ molecules that can be etched with the quantity of etchant activatedby the energy of the overlying beams during the period both beams are onin the overlapping region 52. A reactant, such as CF₄, may be used toetch the underlying silicon oxide. Because the CF₄ will receivesufficient energy to be activated only in the region of the beam overlap52, etching of the silicon oxide with the F activated from the CF₄ willalso occur only in, or very close to, the ovoid region where the overlapovoid meets the silicon oxide layer 323, and thus the recess 358 willhave the same dimension and profile as that in the overlap region 52.

Referring to FIG. 11, after the etching process of FIG. 11 has beenrepeated a number of times, the recess 352 is deepened, and it hassidewalls 358 a extending generally perpendicular to the exposed face326 of the silicon oxide layer 352, and a base 358 d. Then, asprocessing continues, the recess 358 eventually extends through thesilicon oxide layer to form feature 324. To form a circular recesshaving the width of the long dimension D of FIG. 6, the substrate or thebeams may be rotated about the center of the etched feature.Alternatively, to provide a more rounded feature, the substrate may bemoved in a small, on the order of nanometers sized, circular,trapezoidal, pentagonal, etc. pattern to cause rounding of the etchedfeature.

Preferably, in the etching embodiments herein, at least one of the twobeams is pulsed, such that, for example, beam 40 is maintained “on” thesubstrate 320, and the second beam 50 is pulsed on and off. The pulsingof the second beam 50 enables the byproducts of etching to clear theetched feature before the next pulse forms more activated etch speciesfor further etching of the silicon oxide or other layer to be etched.Additionally, the first beam 40 may raster scan the substrate by havingthe substrate support 310 move in the x and y directions, and thismultiple locations on the substrate 310 may be etched. For example, asecond feature may be etched adjacent the initial location, such aswhere recess 328 shown in dashed lines in FIG. 11 is located. Theadjacent feature may be formed by moving the beam 40 back and forthbetween the two different locations, and pulsing the second beam 50 whenthe beam 40 is in a process position.

The beams 40, 50 are shown in an adjacent, overlapped, parallelrelationship in FIG. 9, so that directional etching of the feature 324,with sidewalls generally perpendicular to the face of the silicon oxideor other etched layer, may be accomplished. If the 40, 50 beams onlyintersect at the layer 330 being etched, as is shown in FIG. 14 theywill be shadowed from the base of the recess 358 d by the layer beingetched, and the resulting beam overlap area 374 will be shrunken by theadjacent area 372 of the film layer, resulting in a conical profile ofthe etched feature. Thus, unless a very shallow feature is being etched,the two beams 40, 50 should be provided in a parallel, adjacentoverlapped configuration of FIG. 9.

The example for etching shown in FIGS. 9 to 13 is described in terms ofetching a three dimensional recess having the cross section of theoverlap region of the two beams. To etch a line, the same procedure aswas described for writing/depositing a line with respect to FIGS. 6 to 8may be followed, with the caveat that the parallel, adjacent overlappedbeams of be used. Likewise, to write/deposit a pillar having the overlapprofile of the two beams, the overlapped beams may remain at a singlespot on the substrate, and the substrate may be moved in the z directionto sequentially form atomic size layers of deposition material thereon.

FIG. 15A shows a schematic arrangement of a system for obtaining amultitude of individual depleted beamlets, as opposed to the individualbeams 40, 50 of FIG. 6. The individual depleted beamlets are supplieddirectly from an excitation and a depletion source laser. In thisembodiment, a substrate 320 is shown, and it is held, and moveable in atleast an x, a y and a z direction as was described with respect to FIG.6. In this embodiment, a depleted source beam 1500, and a depletedsource beam 1502, each provided by combining an excitation beam and adepletion beam as described herein with respect to FIGS. 3 to 5, areeach divided into individual beamlets 1500 a-n and 1502 a-n, only two ofeach are shown in FIG. 15. In this embodiment, the beamlets 1500 a-n and1502 a-n are derived from a depleted beam, such that each beamlet hasthe profile of the beam 32 of FIGS. 3 and 4B, each of the beamlets 1500a-n has the same photon energy, and each of the beamlets 1502 a-n hasthe same photon energy. Also, individual pairs of beamlets, where one ofthe pair is from the beamlets 1500 a-n and one of the pair is selectedfrom beamlets 1502 a-n, are combined to create overlap ovoid regions asshown in FIG. 4. In this embodiment, the number of beamlets 1500 a-n isequal to the number of beamlets 1502 a-n, such that the number of ovoidoverlap regions of beamlets is n.

To form the beamlets, a description of forming beamlets 1500 n is given,and the same construct is used to form the beamlets 1502 a-n. Beam 1500is directed to a through a two dimensional Fourier grating system 1504from which a plurality of beamlet elements are emitted. Each beamletelement may be passed through an additional two dimensional Fouriergrating, and each subsequent beam through a further two dimensionalFourier grating, until a large number on the order of 1000 or sobeamlets are formed. The individual beamlets are parallel with oneanother into infinity. Each of the resulting beamlets 1500 a-n, only1502 a and n shown in FIG. 15, are directed at a micro-mirror array1510, having a plurality of micro-mirrors 1500 a-n equal or greater innumber than the beamlets 1500 a-n, and each micro-mirror 1500 a-n isindividually controlled, via a controller 1520, to either reflect thebeamlet reflected thereby to a position to create an overlap region witha beamlet 1502 a-n emanating from beam 1502 on the substrate 320 or to alocation off the substrate 320 or on the substrate but not in anoverlapping relationship with another beamlet.

Referring now to FIGS. 16 and 17, the micro-mirror array 1510 is shownin further detail. As shown in FIG. 16, individual mirrors 1510 a, et.seq. are laid out in a rectangular array, and each of the mirrors 1510a-n are individually controlled to actuate about the z direction asshown in FIG. 17, to position the mirrors 1510 a-n to either direct theindividual beamlets 1500 a-n to a specific location to overlap a beamlet1502 a-n, or in a second position to direct the individual beamlet 1500a-n off the substrate. As shown in FIG. 17, the micro mirrors 1510 d,f,gare positioned to direct the beam in the direction of a substrate 310(FIG. 15A), and mirror 1510 e is moved relative to the position ofmirrors 1510 d,f,g to locate beamlet 1500 e off of the substrate 320.

As previously discussed, beam 1502 is split by one or more Fouriergratings in a Fourier grating system 1504 dedicated therefor, and theindividual resulting beamlets 1502 a-n are directed at individualmicromirrors of a micro-mirror array 1510, to be directed to a discreteoverlap location with a dedicated beamlet of beamlets 1500 a-n. Wherethe system is desired to be run in a deposition mode, i.e., where adeposition precursor gas such as silane is introduced into the chamberto form a silicon deposit in the ovoid overlap regions formed byoverlapping pairs of beamlets 1500 and 1502, the second micro-mirrorarray 1510 and controller 1520 associated with beamlets 1502 a-n may bedisposed of and replaced with a separate mirror, and the beamlets 1502a-n may remain oriented in the direction of the substrate 320 throughoutthe deposition process.

To form features on the substrate surface, for example by deposition,each of the pairs of beamlets, for example beamlets 1500 a and 1502 a,are configured to create an overlap region at a specific coordinatelocation in the x, y and z coordinates of the chamber 300, i.e., anoverlap region in space, which, when the substrate is properly locatedin the z direction, the overlap region is projected onto the substrate320.

FIG. 15B is a schematic representation of an optical system 15000 thatmay be used to generate a pattern of overlapped depleted beamlets havingsingle-nanometer dimension. The pattern may be a regular, repeatingpattern, or the pattern may be a selective pattern, with individualoverlapped depleted beamlets switched “on”, meaning having sufficientenergy to activate a chemical reaction, or switched “off”, meaning nothaving sufficient energy to activate a chemical reaction. The opticalsystem 15000 may be used with any of the apparatus described elsewhereherein for performing a deposition or etch process. FIG. 15B generallyshows three beamlets to represent an array of beamlets that may havethousands, millions, or even billions of beamlets.

The substrate 320 is processed using the optical system 15000, whichcomprises two optical subsystems 15501 and 15502. Each of the opticalsubsystems 15501 and 15502 produces an array of depleted beamlets. Afirst optical subsystem 15501 produces a first array of depletedbeamlets 15901 and a second optical subsystem 15502 produces a secondarray of depleted beamlets 15902. The first and second arrays ofdepleted beamlets 15901 and 15902 are combined or overlapped using abeam splitter 15921 to form an array of overlapped depleted beamlets15941. The array of overlapped depleted beamlets 15941 is focused,magnified, or demagnified by a first imaging element 15961, which may bea first lens, and by a second imaging element 15981, which may be asecond lens, to form an image array of overlapped depleted beamlets15991 that is directed to the substrate 320. Depending on the exactalignment at the beam splitter 15921 of the beamlets produced by the twooptical subsystems 15501 and 15502, the beamlets may partially overlap,meaning a boundary of the energy field of each beamlet, for example the1/e intensity boundary of each beamlet, intersects; the beamlets mayfully overlap, meaning the energy field boundary of one beamlet isentirely inside that of the other beamlet; or the beamlets may becombined, meaning the optical axes of the two beamlets coincide and areparallel within the accuracy of any reasonable measurement.

The first array of depleted beamlets 15901 is produced by directing afirst incident radiation beam 15521 of selected wavelength and intensityto a first diffractive optical element 15561. A first depletion beam15541 is also directed to a second diffractive optical element 15581.The first incident radiation beam 15521 is divided into a first array ofbeamlets 15601 by the first diffractive optical element 15561, and thefirst depletion beam 15541 is divided into a first array of depletionbeamlets 15621 by the second diffractive optical element 15581. Thebeamlet arrays 15601 and 15621 are arranged to coincide at a point on,or within, a first beam splitter 15641 to form a first array of depletedbeamlets 15561, in which substantially all beamlets of the array 15601are combined with a depletion beamlet from the array 15621. The firstarray of depleted beamlets 15661 emerges from the first beam splitter15641 and is directed to a first collimating element 15681 to produce afirst array of collimated depleted beamlets 15701. Some electromagneticradiation may also propagate out of the optical system 15000 at thefirst beam splitter 15641. The first array of collimated depletedbeamlets 15701 passes through a focal element 15721 to form a focusedarray of depleted beamlets 15741, which is directed through a secondbeam splitter 15761 and a second collimating element 15861 to a firstaddressable micro-mirror array 15841, substantially as described inconnection with FIGS. 15A, 16, and 17 above. Some electromagneticradiation may also propagate out of the optical system 15000 at thesecond beam splitter 15761. The first addressable micro-mirror array15841 selectively reflects depleted beamlets back through the secondcollimating element 15861, depending on the orientation of theindividual reflecting elements of the array 15841, as determined by acontroller configured to address and adjust each reflecting elementindividually. The second collimating element 15861 focuses the reflectedbeamlets back to the second beam splitter 15761. Beamlets reflected fromthe second beam splitter 15761 form a patterned array of depletedbeamlets 15871, reflecting the configuration of the first addressablemicro-mirror array 15841. Beamlets that were reflected from the firstaddressable micro-mirror array 15841 confer additive energy thepatterned array of depleted beamlets 15871, such that the pattern arrayof depleted beamlets 15871 may contain depleted beamlets of a firstenergy and depleted beamlets of a second energy different from the firstenergy. The patterned array of depleted beamlets 15871 is directedthrough a third collimating element 15881 to form the first array ofdepleted beamlets 15901 bearing the energy pattern defined by theaddressable micro-mirror array 15841.

A similar process is performed to form the second array of depletedbeamlets 15902 using the second optical subsystem 15502, which issimilar or identical to the first optical subsystem 15501. A secondaddressable micro-mirror array 15842 may be used to pattern the secondarray of depleted beamlets 15902. At least one of the arrays 15901 and15902 has a pattern of beamlet energies that may have depleted beamletsof two different energy values. If both beamlet arrays 15901 and 15902are patterned according to energy, the two patterns may be the same ordifferent. Thus, the image array of overlapped depleted beamlets 15991may be configured to have overlapped energy fields at the surface of thesubstrate 320 that have one, two, or four different energies. It shouldbe noted that the beam splitters used in the optical system 15000 mayresult in some power losses through the system, so the power level ofthe original incident beams and depletion beams are selected tocompensate for those losses.

Depending on the precursors present in the energy fields, such anoptical system may be used to concurrently perform deposition andetching processes at different locations on one substrate. For example,the image array of overlapped depleted beamlets 15991 may be arranged,by operation of the addressable micro-mirror arrays 15841 and 15842, todeliver a plurality of overlapped energy fields having four differentenergies to the substrate 320 such that a first portion of theoverlapped energy fields has an energy that activates a depositionprecursor provided to the substrate in a gas mixture, a second portionof the overlapped energy fields has an energy that activates an etchprecursor provided to the substrate in the gas mixture, and a thirdportion of the overlapped energy fields has an energy that does notactivate any precursors. In this way, a first plurality of locations onthe substrate 320 undergo a deposition process, a second plurality oflocations on the substrate 320 undergo a concurrent etch process, and athird plurality of locations on the substrate 320 are not processed. Forexample, if a gas mixture comprising silane and CF₄ is provided to achamber with the optical system 15000 of FIG. 15B, a substrate may beprocessed by performing thousands of single nanometer-sized depositionprocesses at a first plurality of locations on the substrate usingenergy that is selected to activate only the silane, while concurrentlyperforming thousands of nanometer-sized etch processes at a secondplurality of locations on the substrate, different from the firstplurality of locations, using energy that is selected to activate onlythe CF₄, and all the energy for activating the precursors is emittedconcurrently by four radiation sources through the optical system 15000.In this way, a deposition process may be performed at a nanometer-sizedlocation on the substrate while, concurrently and only about 40 nm away,an etch process is performed at another nanometer sized location on thesame substrate.

A similar method and apparatus may be used to selectively removematerial from a semiconductor substrate. The semiconductor substrate maybe disposed in a processing chamber, where a pattern of overlappingdepleted beams or beamlets is directed to the substrate. Concurrently, aselective removal gas such as HCl or Cl₂ may be provided to theprocessing chamber at an area adjacent to the substrate. The wavelength,intensity, and duration of the radiation of the beams or beamlets isselected to activate the selective removal gas to a reactive state sothat activated species of the selective removal gas react with specieson the substrate that are to be removed.

FIG. 15C is a schematic representation of an optical system 15001according to another embodiment that may be used to generate a patternof overlapped depleted beamlets having single-nanometer dimension. Theoptical system 15001 uses properties of radiation to collinearly combineor overlap beams of electromagnetic radiation, reducing power lossesthat might be encountered using the optical system 15000 of FIG. 15B. Afirst incident beam or pulse 15523 is passed through a first diffractiveoptical element 15563 to form a first array of beamlets 15603, which arepassed through a first collimating element 15683 to form a firstcollimated beamlet array 15703. A first polarizer 15703 polarizes thebeamlets of the first collimated beamlet array 15703 to form a firstpolarized beamlet array 15763.

A second incident beam 15543 is likewise passed through a seconddiffractive optical element 15583 to form a second array of beamlets15623, which are passed through a second collimating element 15693 toform a second collimated beamlet array 15713. The second collimatedbeamlet array 15713 is passed through a second polarizer 15743 to form asecond polarized beamlet array 15783.

The first polarized beamlet array 15763 and the second polarized beamletarray 15783 have polarization states that are related in a way that theycan be collinearly combined by a first polarized beam combiner 15803.The polarization state of the first polarized beamlet array 15763 may beorthogonal to the polarization state of the second polarized beamletarray 15783. The first polarized beamlet array 15763 and the secondpolarized beamlet array 15783 are aligned such that each beamlet of thefirst polarized beamlet array 15763 is substantially coaxial andparallel to a corresponding beamlet of the second polarized beamletarray 15783 as the two beamlet arrays exit the first polarized beamcombiner 15803, by aligning each corresponding beamlet from each arrayas closely as possible to hit exactly the same spot on an opticallyactive surface 15813 of the polarized beam combiner 15803. The resultingarray of combined beamlets 15823 thus comprises a plurality of beamlets,each of which may have a Gaussian energy profile similar to thatdescribed in connection with FIG. 1B. Alternately, the two beamletsarrays may be aligned so that each beamlet of one beamlet array overlapswith a corresponding beamlet of the other beamlet array to form an arrayof overlapping beamlets, each of which may have an every profile similarto that described in connection with FIG. 1C. To form an array ofoverlapping depleted beamlets having an overlap pattern as shown in FIG.4, the first and second polarized beamlet arrays 15763 and 15783 may beslightly mis-aligned at the first polarized beam combiner 15803.

An array of depletion beamlets 15824 may be formed in a substantiallysimilar manner using the optical subsystem 15504, which is similar oridentical to the optical subsystem 15503. A first depletion beam 15524and a second depletion beam 15544 are divided into beamlets by a thirddiffractive optical element 15564 and a fourth diffractive opticalelement 15584, respectively. The beamlets are collimated and polarizedsuch that a second polarized beam combiner 15804 combines the beamletsto form the array of depleted beamlets 15824, each beamlet thereofhaving an energy profile similar to that described in connection withFIG. 2B. To form an array of overlapping depleted beamlets having anoverlap pattern as shown in FIG. 4, first and second polarized depletionbeamlet arrays 15764 and 15784 may be slightly mis-aligned according tothe same pattern as the mis-alignment of the first and second polarizedbeamlet arrays 15763 and 15783. Then, the resulting array of depletionbeamlets 15824 is aligned with the slightly mis-aligned array ofbeamlets 15823 so that each depletion beamlet coincides with acorresponding beamlet from the array 15823, as described in connectionwith FIG. 3A. The overlap in the depletion beamlets and the normalbeamlets described above, when combined in this way, results inoverlapped depleted beamlets.

The array of beamlets 15823 may be collinearly combined with the arrayof depletion beamlets 15824 by using a wavelength selective reflector15922. Such a reflector reflects electromagnetic radiation of onewavelength, or a narrow band of wavelengths, while transmittingelectromagnetic radiation of other wavelengths. Such reflectors areknown in the art, and may be made by forming alternating layers ofmaterials having different refractive indices. The materials may beselected, and the thicknesses of the layers may be determined, toprovide virtually any desired degree of wavelength selectivity. In theembodiment of FIG. 15C, the depletion beams 15544/15524 may have adifferent wavelength from the incident beams 15523/15543. The wavelengthselective reflector 15922 is configured to reflect electromagneticradiation at the wavelength of the depletion beams 15544/15524. Aligningthe depletion beamlet array 15824 with the beamlet array 15823 on thewavelength selective reflector 15922 results in a collinearly combinedarray of depleted beamlets 15942. The array 15942 may finally befocused, magnified, or demagnified by the imaging optical elements 15962and 15982, which may be imaging lenses, to form an image of overlapped,depleted beamlets at the substrate 320. It should be noted here that theoptical system 15001 may also be configured with a wavelength selectivereflector 15922 that reflects the wavelength of the incident beams15523/15543 while transmitting the wavelength of the depletion beams15524/15544.

FIG. 15D is a schematic representation of an optical system 15002according to another embodiment that may be used to generate a patternof overlapped depleted beamlets having single-nanometer dimension. Theoptical system 15002 is similar in most respects to the optical system15001 of FIG. 15C, except that the addressable micro-mirror arrays15841/15842 described in connection with FIG. 15B are included. Thepolarizers 15743/15744 are moved to the opposite side of theirrespective polarized beam combiners 15803/15804 so the respectivebeamlets arrays 15783/15784 will pass through the polarizing beamsplitters 15803/15804 at first, be polarized by the polarizers15743/15744, and reflect from the addressable micro-mirror arrays15841/15842.

In an alternate embodiment, 15543 and 15524 may be incident beams and15523 and 15544 may be depletion beams. In such an embodiment, the twoincident beams 15543/15524, divided into beamlet arrays 15713/15714 maybe digitized (i.e. individual beamlets switched on or off) by theaddressable micro-mirror arrays 15841/15842, and the resulting patternedbeamlet arrays combined with depletion beamlet arrays usingpolarization. The resulting digitized depleted beamlet arrays15823/15824 may then be combined or collinearly overlapped using thewavelength selective reflector 15922. In such embodiments, thewavelength selective reflector 15922 may selectively reflect the twowavelengths of the incident beam 15524 and the depletion beam 15544. Insuch an embodiment, the wavelengths of the incident beams 15543/15524are preferrably different and the wavelengths of the depletion beams15523/15544 are preferrably different to facilitate combination oroverlap at the wavelength selective reflector 15922. Such reflectors areknown in the art, and may be made by applying two Bragg coatings to asubstrate, each selective to one wavelength. Thus, a first wavelength isreflected by the first coating and a second wavelength is reflected by asecond coating, the two wavelengths corresponding to the incident anddepletion beams 15524/15544. Note that the differing path lengths of thetwo beams, due to the different penetration depths into the wavelengthselective reflector 15922, may be addressed by adjusting alignment ofthe beamlet arrays 15714 and 15764.

As described above in connection with FIG. 15B, such a configuration maybe used to make an array of overlapped depleted beamlets 15992 at thesurface of the substrate 320 that has a variety of beamlet energies.FIG. 15E is a view of a portion 15900 of the substrate 320 with thearray of overlapped depleted beamlets 15992 illuminating the surfacethereof. The array 15992 comprises a first plurality of overlappedbeamlets 15902 having a first energy and a second plurality ofoverlapped beamlets 15904 having a second energy different from thefirst energy. The first energy may be an energy that activates a firstprecursor to perform a first process at the surface of the substrate 320in the areas illuminated by the first plurality 15902. The second energymay be an energy that activates a second precursor to perform a secondprocess at the surface of the substrate 320 in the areas illuminated bythe second plurality 15904.

The two different energies may be realized by operation of theaddressable micro-mirror array 15841 such that a selected beamlet fromthe array 15783 is not returned through the polarizer 15743. The resultat the corresponding location on the wafer 320 is that the irradiatedarea of the substrate is illuminated by radiation only from the incidentbeam 15523 without any contribution from the incident beam 15543,resulting in radiation of lower energy than if both incident beams15523/15543 are combined. In this way, adjacent locations on thesubstrate 320 may be illuminated by radiation from one incident beam orfrom two overlapping incident beams.

Precursors may be provided to the substrate 320 in a single gas mixturesuch that wherever the gas mixture encounters the first energy, thefirst precursor is activated and wherever the gas mixture encounters thesecond energy, the second precursor is activated. Each of the first andsecond precursors may independently be a deposition precursor or an etchprecursor so that the first process may be a deposition process or anetch process and the second process may be a deposition process or anetch process. In this way, beamlets having dimensions less than 10 nmmay be directed to the surface of the substrate 320 in a substantiallyperpendicular and collimated fashion to perform precise materialprocesses avoiding the shadowing phenomenon described in connection withFIG. 14.

In some embodiments, the second energy may activate both the first andthe second precursors. In such embodiments, the concentration of thefirst and second precursors in the gas mixture may determine the natureof the process performed by the combined activated first and secondprecursors. If the first precursor is a deposition precursor and thesecond precursor is an etch precursor selective to species depositedfrom the first precursor, then the equivalent amounts of the first andsecond precursors determine whether the process activated by the secondenergy is an etch process or a modified deposition process. If the etchprecursor is in substantial excess, an etch process may result. If theetch precursor is not in substantial excess, a modified depositionprocess, such as a selective deposition process (e.g., a process inwhich the etch rate of the activated etch precursor is faster in someareas than in others), may result.

In some embodiments, the wavelength of the incident beams 15543 and15524 of FIG. 15D may be selected based on absorption cross-section oftwo precursors provided to the chamber in the gas mixture. In suchembodiments, overlapped depleted beamlets may be directed to thesubstrate that have three different energies. The first energy may havea first wavelength, the second energy may have a second wavelength, andthe third energy may have a combination of the first and secondwavelengths. The first wavelength may be preferentially absorbed by thefirst precursor and the second wavelength may be preferentially absorbedby the second precursor. The fluence of each laser may be furtherselected, along with concentration of the precursors, to achievespecific levels of activation of each precursor at specific locations onthe substrate to perform highly selective material processes in areassmaller than 10 nm, in some cases smaller than 1 nm, and separated by 20nm or less concurrently. In such embodiments, the wavelength selectivereflector 15922 may be selective to more than one wavelength. Suchreflectors may be made by forming a dual-wavelength selective reflectinglayer on a transmissive substrate, the layer comprising a first layerselective to a first wavelength and a second layer selective to a secondwavelength, the different wavelengths being determined by the refractiveindices and thicknesses of the layers deposited on the substrate.

Referring to FIGS. 18A to 18F, the deposition of two lines and a pillaron a portion 1530 of the surface of substrate 320 is shown. Referringfirst to FIG. 18A, the surface 1530 of the substrate 320, without thelines or pillars is shown. Then, as shown in FIG. 18B, three ovoidoverlap regions, 1532, 1534 and 1536 are formed on the substratesurface, corresponding to locations 1542, 1544 and 1546 on surface 1530.Then, by applying the silane precursor as previously described a silicondeposition layer in the contour and size of the ovoid regions is formed.Ovoid overlap regions 1532-1536 are locations fixed three dimensionallyin the chamber 300, whereas the locations 1542-1546 are locations fixedon the surface 1530 of the substrate 320.

Referring now to FIG. 18C, there is shown the deposited ovoid featuresthat were deposited in FIG. 18B at locations 1542-1546, but only ovoidregion 1532 is formed on the substrate 320, over the previouslydeposited material at location 1542, such that an additional layer ofmaterial is formed over the previously formed material at location 1542.The ovoid regions that formed deposition material at locations 1544 and1546 are not present, which occurs because beamlets 1502 and or 1500used to form an overlapping region at those location were diverted bythe micro-mirrors associated therewith in the micro-mirror array 1510.

Referring now to FIG. 18D, the substrate is shown with a plurality ofdeposition layers stacked one atop the other at location 1542, whichwere formed by repeating the process described with respect to FIG. 18C,and an overlap region 1534 is shown projected onto the substrate 320adjacent to the previously formed layer at location 1544. This isaccomplished by moving the substrate to the left in the figure, suchthat the ovoid region having fixed coordinates in the chamber appear tothe right of the previously deposited ovoid layer at location 1544. Atthis point reactant gas is introduced, or is already present, to form adeposition layer at location 1544 a adjacent to, and overlapping,location 1544. Then, as can be seen in FIG. 18E, the substrate 320movement and pulsing of one or both of the beamlets 1500 a-n, 1502 a-ndedicated to ovoid region 1534 has resulted in a plurality of ovoiddeposition regions extending from location 1544 to 1544 n on thesubstrate surface 1530 to form a line extending from the right to theleft in the Figure.

Referring now to FIG. 18F, the substrate 320 has now been moved in the Ydirection, perpendicular to the direction in which the substrate 320 wasmoved to form the line 1534, and only ovoid region 1536 is projected onthe surface 1530, such that the ovoid projected region 1536 overlies,and extends in the Y direction from, the film layer formed at location1546. As demonstrated by dashed line arrow 1540, a line 1536 may bewritten in the Y direction by further incremental movements of thesubstrate 320 in the Y direction followed by forming the ovoid region1536 to form a yet further partially overlapping, partially extending,ovoid deposition layer on previously formed layer 1536 a . . . , until aline of a desired thickness is written. To extend the height of thelines 1544 and 1546 in the Z direction of FIG. 6, the lines 1546 and1544 are overwritten using the same sequence of operations as described.

To enable selective projection of the beamlets to form pillars andlines, the controller 1520 includes a programmable microprocessor andinterface software configured to bend each or any of the micro-mirrorsof the micromirror array 1510 following an instructed patter to writepillars and lines across the entire surface 1530 of the substrate 320.Multiple lines, and multiple pillars may be written simultaneously,resulting in significant throughput in line writing by the system.Additionally, by proper simultaneous x and y direction movements, linesextending in directions other than parallel to the x or Y directions maybe written. Additionally, to maintain a consistent size of theprojection of the ovoid region on the substrate, the substrate may alsobe moved in the z direction where a material layer is being depositedover a pre-deposited film layer.

Referring now to FIGS. 17 and 19, a second configuration for projectingoverlapping regions of two depleted beams is shown. In this embodiment,two separate depleted beams 1500 and 1502 are passed through Fouriergrating systems 1504 to form multiple derivative beamlets 1400 a-n and1502 a-n, and these beamlets are, as described with respect to FIG. 15,directed at, and selectively individually reflected in a first directionor a second direction, by a controller 1520 controlling the position ofthe mirror. However, in contrast to the embodiment of FIG. 15, in thisembodiment, the individual beamlet 1500 and 1502 pairs to form theoverlap regions on the substrate 320 are delivered to the wafer with apartial overlap and in a nearly collinear alignment, where the axes ofeach beamlet is parallel in infinity, or near infinity (beam spacing ismaintained along the length of the beamlets). To provide this alignment,a beam combiner 1560 is provided where the beamlets 1502 a-n passthrough the combiner 1560, and the beamlets 1500 a-n are reflected atthe combiner 1560 in the direction of the substrate and nearlycollinearly aligned, and parallel to, the beamlets 1502 a-n, such thateach pair of beamlets, for example beamlets 1500 a and 1502 a, have thealignment show and described with respect to beams 40, 50 of FIG. 10herein.

In this configuration, etching or deposition of the species on thesubstrate 320 surface is accommodated. Because the beams are directedparallel to, and partially overlapped with, one another, the overlapregion extends from the substrate 320 to the window 350 in the chamber300, and the combiner is located exteriorly of the chamber 300.

In the same manner as described with respect to FIGS. 18A to 18F, thebeamlets may be used to deposit features on the substrate surface usingselective reflecting of beamlets to or from specific locations in thechamber 300. However, as the overlap region of each pair of beamletsextends the height of the chamber 300 above the substrate, the locationof the overlap region may be considered fixed only in the x and ydirection of the substrate because movement of the substrate in the Zdirection (FIG. 6) will not result in a change in the size of, orcomplete loss of, the overlap regions on the substrate. Additionally,this embodiment is highly desirable for etch processes, as the overlapregion is columnar and will not be shadowed from the base of a featurebeing etched would occur with the beamlets of FIG. 15.

Referring now to FIG. 20, a sheet beam arrangement for photonicprocessing of a workpiece is described. A sheet beam projector 1600 ofthis embodiment replaces the two dimensional Fourier Grating 1504 of theprevious embodiment shown and described with respect to FIGS. 15 to 17.In this embodiment, a depleted beam 1602 having an excitation region ofhigh energy photons having a distinctive skirt or waste which isdepleted, as is also shown and described with respect to FIGS. 3A and Bherein, is directed through a first plano-convex lens 1604 and a firstplano-concave lens 1606 to form an expanding sheet 1608, and thenredirected into the sheet beam 1610 by passing through a second planoconcave lens 1612 and second plano-convex lens 1612. A linear or lineconfigured plurality of micromirror array 1620 is located in the line ofsheet beam 1610, at a 45 degree angle with respect thereto, such thatthe sheet beam 1610 is transposed and reflected 90 degrees and thus inthe direction of chamber 300. Chamber 300 has the same basicconfiguration of chamber 300 except where noted, so the descriptionthereon will not be repeated. A single window 350, which has a lengthlarger than the full width of the sheet beam, is disposed in the chamberlid 304. Thus, the sheet beam, which has a central excitation region ofhigh energy photons and a depleted skirt or waste region to either sidethereof, is projected into the chamber 300.

As described with respect to the Fourier grating 1504 and micromirror1510 embodiment of FIGS. 15 to 17 herein, in this embodiment a secondsheet beam projector 1600, and micromirror array 1620 are provided, andthe sheet beam projected thereby is likewise directed to the workpiece320, in a parallel, partially overlapping condition, such that a verynarrow line, in which the overlap of the excitation beam portions of thetwo sheet beams overlap on the substrate. As with the previousembodiments wherein, it is contemplated that sheet beams having anexcitation beam portion having high energy photons may be on the orderof 50 or less nanometers wide, and as small as 20 nanometers wide, andan overlapping region, in which reaction will occur to reactantintroduced or maintained over the workpiece, can be maintained below 20nm wide, such as 5 nm to less than one nm wide.

Additionally, in this embodiment, as also described with respect to theembodiment shown in FIGS. 15 to 17, one of the sheet beams 1600 may bedirected to the workpiece 320 by a unitary, i.e., a non micro mirrorarray 1620, mirror. As the presence of the two beams together at theworkpiece is required for a reaction to occur, only one of the beamsneed be redirected or pulsed to effectively start and stop a reaction.Additionally, one beam may be configured as a depleted beam(s), and thesecond as a depleted sheet beam. Thus, by relatively partiallyoverlapping the spot beam at discrete locations on the line on thesubstrate by the projected sheet beam, individual features may be formedin discrete locations over the length of the line of the projected sheetbeam.

Referring now to FIGS. 21 and 22, the configuration of the micromirrorarray 1620 is shown. In contrast to the micromirror array of theprevious embodiment, the micromirror array 1620 includes only a singlerow of mirrors 1620 a-n, and each mirror is individually addressable bya controller 1630 connected to an actuator on each of the micromirrors1620 a-n by a communication line 1632. The positioning of each mirror ofthe micromirror array 1620 is the same as that shown in the micromirrorarray of FIG. 17, wherein the mirror may be maintained at a 45 degreeangle to an incoming beam, or canted or rotated about a z axis (FIG. 21)to deflect the portion of the sheet beam 1610 reflected by theindividual micromirror 320 a-n away from the workpiece 320.

Referring now to FIGS. 23 and 24, the use of overlapping excitationportions of two line beams 310 is shown. In FIG. 23, a workpiece 320 isdisposed on support 310, which projects above the base of the chamber300. An overlap region 1640 of two sheet beams extends across theworkpiece as a thin line, and outwardly therefrom over the face of thesupport 310. The maximum length of the overlap region 1640 need be thewidth of the workpiece, and, the length of the linear overlap region1640 may be adjusted by blanking the portions of the sheet beam withmicromirrors at opposed ends of the micromirror array 1620. Then, byintroducing (or maintaining a previously introduced) reactant species inthe linear overlap region 1640, a feature 1650, created by the effect ofthe reactants, is formed over the overlap region 1640, as is shown inFIG. 24, wherein the workpiece has been rotated 90 degrees about itscenter 380. The feature 1650 can be a deposited feature, an etchedfeature, or other material feature, as have been previously describedherein.

The workpiece may be moved in the x, y, z and theta directions shown onFIG. 23. Thus, after forming feature 1650, the substrate may be moved inthe x direction, while at least one of the two sheet beams 1610 areblanked into a non-overlapping condition by the micromirror array 1620,and then the two sheet beams directed again to overlap at an overlapregion 1640 to form a feature on or in the workpiece with a reactant.Thus, by moving the workpiece, and selectively blanking or not blankingportions of the sheet beam, continuous or discontinuous linear featuresmay be formed on the workpiece, such as features 1650, 1650 a and 1650 bof FIG. 24.

After forming the linear features, the workpiece may be rotated, andagain the two sheet beams caused to overlap at the workpiece in thepresence of a reactant, to form additional continuous or discontinuouslinear features across the overlap region, discontinuity provided by theselective blanking of individual ones of the micromirrors 1620 a-n bythe controller 1630. As shown in FIG. 24, as a result of blanking of aportion of the micromirrors 1620 a-n, a discontinuous linear overlapregion is formed on workpiece, having discrete overlap regions 1640 a-h.In the overlap regions, non-blanked micromirrors of the micromirrorarray 1620 project the portions of each sheet beam to the workpiece, butin the gaps in the linear arrangement of overlap regions 1640 a-h ofFIG. 23, portions of at least one of the sheet beams 1620 are blanked byone or more of the micromirrors of the micromirror array 1620. Thesmallest length segment that may be discretely formed as an overlap isthus on the order of the size of an individual mirrors. Where theposition of one set of micromirrors for one sheet beam is offset by onehalf the length of the individual micromirrors 1620 a-n, then thesmallest length can be ½ the length of an individual micromirror, wherethe micromirrors in both arrays 1620 are the same.

Referring still to FIG. 23, the areas where the overlap sub regions 1640a-h are formed will have a reaction occur with reactant. Thus, if forexample the features 1650, 1650 a and 1650 b are lines formed bydeposition from a precursor, then additional lines may be written ordeposited on the workpiece 310 where the segments 1640 a-h of theoverlap region are present. For example, a line may be written inoverlap region 1640 f between lines 1650 and 1650 a. Alternatively, ifan etching reactant for the previously deposited lines 1650, 1650 a and1650 b is introduced as the reactant, then line 1650 can be etched awaywhere overlap region 1640 g extends thereacross. Thus, it is shown thatby using sheet beams to create continuous or discontinuous linearoverlap regions. Features may be deposited and etched to form lines,pillars, and the like, and materials may also be selectively etched toform apertures and trenches therein.

Referring now to FIG. 25, there is shown an electron energy diagram fora precursor to be used to enable reaction in overlap regions of the twodepleted beams such as two STED depleted beams. A precursor useful inthe operation of the depleted beam system of the present invention hasthe properties shown in FIG. 25, i.e., upon the receipt of the firstbeam E₁, the electrons in the atoms or molecules of the precursor moveto an intermediate energy state, and in the skirt regions of the twooverlapping beams, the electrons of the precursor move down from theintermediate state by exposure to the STED (depleted) beam E_(1D) in theskirt region. Then, when the same atom or molecule is exposed to thesecond depleted beam E₂, the excited electrons which have remained atthe intermediate state move to the antibonding state, and any electronsin the antibonding state that are exposed to the second depletion beamE_(2D) (in the skirt region of the beam) move down from the antibondingstate. Once in the antibonding state, the atoms and molecules are highlysusceptible to separation or reaction to form deposits or etch adjacentmaterials.

As described herein, the partially overlapping beams may be used fordeposition and etching processes. Traditional deposition reactions, suchas those in which two or more precursors combine to yield a depositionmaterial, will occur in the overlap region to deposit a product ofreaction within the area of beam overlap. Atomic layer deposition (ALD)processes may also be activated using the overlapping depleted beamshereof. In those reactions, any or all of the precursors used to formthe deposition material may be activated to deposit on a substrate onlyin the overlap region. Thus, the initial (or an intermediate) precursorof a multi-precursor ALD process may be deposited by activation, and thesubsequent precursors introduced to react therewith without the need foractivation, and deposition will occur only at the sites where theinitial (or intermediate) precursor was deposited. This may be repeatedto form lines, pillars, etc., of a desired dimension. Where the initialprecursor requires activation, there is no need to remove the initially(and intermediate, if needed) precursor from the non-reacted sites,because no reaction was activated at those sites.

This same paradigm may be used for atomic layer etching of an underlyingsubstrate material. In one aspect, the first reactant precursor may be“blanket” deposited over the entire surface of the substrate, and thefinal reactive precursor may be that which is activated by overlappingbeams, resulting in deposited or etched features only in the overlapregion. The overlapping beams may be raster scanned over the materialblanket deposited from the first precursor to form features at thedesired locations.

As described herein, two different beams of photons are provided in alocation such that the energy in the overlap region is a combination ofthe photon energy of both beams, the size of the overlap region may beselected as equal to (full overlap) or significantly smaller than, thecross section of either beam, and by introducing a precursor to theoverlap region, a deposition or etching reaction can be caused to occuronly in, or directly adjacent to the overlap region. Further, byemploying depleted regions, wherein the effect to the photons in theskirt of the Gaussian profile of the beam is counteracted with adepletion beam, in one aspect a STED depleting beam surrounding anexcitation beam, the occurrence of reaction outside of the overlappingarea of the non-depleted center regions of the beams is prevented. Thus,as a beam having a non-depleted diameter as small as 20 nanometers maybe formed, an overlap region as small as the single nanometer digits, orless than 1 nanometer, may be formed, such that very small features on asubstrate may be formed therein.

Further, the embodiments herein contemplate using circular beams which,when partially overlapped, form ovoid regions. Other beam shapes, suchas elliptical depleted beams, which when overlapped end to end will forma more circular overlap region, and rectangular depleted beams, whichwhen overlapped corner to corner will form a rectangular overlap region,are specifically contemplated herein. Additionally, more than two beamsmay be combined and overlapped to form the reaction region. In thiscase, the ovoid region of FIGS. 18 may be modified to provide a threetrilobular profile of the region using three partial overlapping beams.In this case the total energy of three beams, but not any two, is chosento cause the deposition or etch reaction within the profile of thetrilobular region.

Additionally, beam energies and reactants (precursors) may be chosensuch that the combined energies of the beams are sufficient to cause thereactant to react for deposition or etch purposes, but the energy wherethe non-depleted excitation core of the beam overlaps the depletedregion of the other beam will not result in deposition, therebyresulting in sharp definition of the resulting deposited or etchedfeature corresponding to the size and profile of the overlap region.

In general for the processes described herein, the excitation beamand/or the depletion beam may be continuous wave or pulsed beams. If thebeams are pulsed, both the excitation beam and the depletion beam areenergized and emitting radiation for a time period sufficient to excitespecies in a process gas, typically from about 500 nsec to about 1 msec,for example about 100 μsec to about 800 μsec. In addition, in a pulsedembodiment, the beams are typically de-energized between pulses for atime period less than a decay time, for example a half-life, of excitedspecies in the process gas. Thus, the excitation and/or depletion beamswill typically have a pulse frequency of about 500 Hz to about 20 MHz,for example 10 kHz to 50 kHz. The pulse duration and frequency depend onthe composition, density, and temperature of the gases being activated.Smaller molecules directionally have larger ionization potentials andless likelihood of engaging in deactivating collisions at a givendensity and temperature. Higher densities make deactivating collisionsmore likely. Higher temperatures provide latent thermal energy tosupplement the activating energy of the beams, leading to a lowerexcitation threshold.

The two excitation beams and the two depletion beams in an overlappedembodiment may all be pulsed at the same time, or the depletion beamsmay be pulsed with timing that encompasses the pulses of the excitationbeams, so that the depletion beams are energized whenever the excitationbeams are energized. In another embodiment, the depletion beams may becontinuous wave while the excitation beams are pulsed. Embodiments wherethe depletion beams are energized for substantially longer times

Additionally, although the embodiments herein have been described interms of additive and removal processes, other processes arespecifically contemplated where very fine features need to be defined orformed in a material. For example, the combined energies of properenergy may be used to expose photoresist to smaller feature sizing, wellbelow the 20 nm cross section of a single depleted beam. Likewise, thecombined beams may be used to activate a material such that laterflowing of a gas or liquid thereover causes a reaction in the writtenarea. They may be used for fine feature annealing, and for forming finefeature objects other than semiconductor device features, for examplefine pith very thin lined gratings and the like.

While the foregoing is directed to embodiments of the present invention,other and further embodiments of the invention may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

We claim:
 1. A method of supplying reactant activation energy to asub-micron area, comprising: providing a first photon energy beam havinga core region and a surrounding depleted region; providing a secondphoton energy beam having a core region and a surrounding depletedregion; and positioning the first photon energy beam and the secondphoton energy beam to overlap in a first overlap region wherein theoverlap area of the first overlap region is less than an area of eitherthe first photon energy beam or the second photon energy beam.
 2. Themethod of claim 1, further including: providing a workpiece at the firstoverlap region; causing an energy related effect to a first location ofthe workpiece at which the first overlap region is formed, and thenmoving the workpiece, to position the overlap region of the first andsecond photon energy beams at a location on the surface of the workpiecedifferent than the first location.
 3. The method of claim 2, wherein,during the movement of the workpiece, the first and second photon energybeams do not overlap.
 4. The method of claim 3, further includingpulsing at least one of the first and second photon energy beams.
 5. Themethod of claim 2, wherein the different location of the surface of theworkpiece partially overlays the first overlap region.
 6. The method ofclaim 1, wherein the first photon energy beam and the second photonenergy beam are parallel and overlap along at least a portion of thelength of each photon energy beam.
 7. The method of claim 1, wherein thefirst photon energy beam and the second photon energy beam intersect atthe first overlap region.
 8. An apparatus for the formation ofsub-micron features on a workpiece, comprising: a first depletion beamgenerator; a second depletion beam generator; a moveable substratesupport; and a blanking shutter between the moveable substrate supportand the first and second depletion beam generators.
 9. The apparatus ofclaim 8, wherein the blanking shutter is a moveable mirror.
 10. Theapparatus of claim 8, wherein the blanking shutter is operable to causethe first or the second depletion beam to change condition at themoveable substrate support.
 11. The apparatus of claim 8, wherein eachdepletion beam generator further comprises a beam splitter and amicromirror array.
 12. The apparatus of claim 11, wherein at least onebeam splitter comprises a Fourier grating.
 13. The apparatus of claim12, wherein the Fourier grating is a two dimensional Fourier grating.14. The apparatus of claim 11, wherein the Fourier grating splits thebeam into a plurality of beamlets.
 15. The apparatus of claim 14,further including a beam combiner positioned between the micromirrorarrays of the first and the second depleted beam generators, such thatbeamlets from a first of the depleted beam generators pass through thecombiner, and the beamlets from the second of the depleted beamgenerators are reflected at the combiner.
 16. The apparatus of claim 15,further including a controller capable of independently moving each ofthe mirrors of the miocromirror array.
 17. A method of causing areaction at a sub-micron region of a substrate; comprising; providing atleast two beams having an excitation portion of a first energy levelsurrounded by a first depleted region; providing at least two beamshaving an excitation portion of a second energy level surrounded by asecond depleted region; selectively partially overlapping the firstdepleted region and the second depleted region at the surface of thesubstrate to form a reaction region having an area smaller than theprojected area of either excitation portion on the substrate, such thata first of the beams of the first energy level at least partiallyoverlaps a first of the beams of the second energy level at thesubstrate, and a second of the beams of the first energy level at leastpartially overlaps a second of the beams of the second energy level atthe substrate; and providing at least one reactant species at thereaction region and performing a reaction involving the reactant speciesin the reaction region but not in adjacent regions of the substrate. 18.The method of claim 17, further including interrupting the passage ofthe beams of at least one of the first energy level or the second energylevel such that the beams do not reach the workpiece; moving thesubstrate; and causing only one of the interrupted beams to again reachthe substrate and overlap with the corresponding one of the beams of theother energy level in the presence of the reactant to cause the reactionin the reaction region.
 19. The method of claim 18, wherein thesubstrate is moved in the plane of the substrate before the one of theinterrupted beams again reaches the substrate.
 20. The method of claim17, wherein the reactant species is a deposition or etching reactant.